goodhouse



Feb. 13, 1962 c. J. GOODHOUSE SWITCH AC'TUAT ING TIMER 2 Sheets-Sheet 1Filed Feb. 24. 1959 INVENTOR. v far/ J iaaa iaz/se, BY

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Feb. 13, 1962 c. J. GOODHOUSE SWITCH ACTUATING TIMER Filed Feb. 24. 19592/ as 32 a 34 2 sheets sheet 2 INVENTOR.

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United States Patent Ofilicc 3,020,772 Patented Feb. 13, 1962 3,020,772SWITCH AKITUATING TIMER Carl J. Goodhouse, Litchfield, Conn, assignor toGenernl Time Corporation, New York, N.Y., a corporaticn of DelawareFiled Feb. 24, 1959, Ser. No. 794,975

' 4 Claims. (Cl. 74-54) The present invention relates generally toelectric switch actuating timing devices and concerns a timerparticularly well suited for controlling a defrosting cycle inrefrigerators.

The primary object of the invention is to provide a novel switchactuating timer capable of reliably operating a switch through a shorttimed interval during a relatively much longer timing cycle. In thisway, the timer can effectively control a refrigerator defrosting cyclelasting but a few minutes but which occurs only once or twice a day.

it is also an object of the invention to provide a timer as describedabove which snap-actuates common, inex pensive switch components toavoidarcinglor fluttering of switch contacts, even though the timeroperates the switch through only a small fractional part of the totaltiming cycle.

It is a further object to provide a reliable timer having the abovecharacteristics which is exceptionally compact and quite inexpensive tomanufacture.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings in which:

FIGURE 1 is a section of a switch actuating timer con structed inaccordance with the present invention;

FIG. 2 is a section taken approximately along the line 22 of FIG. 1; and

FIGS. 3, 4 and 5 are fragmentary views similar to FIG. 1, showing instop-motion form, the operation of the timer.

While the invention will be described in connection with a preferredembodiment, it will be understood that I do not intend to limit theinvention to that embodiment. On the contrary, I intend to cover allalternatives, modifications and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claims.

Turning first to FIGS. 1 and 2, there is shown a switch actuating timerembodying the invention which is effective to operate an electric switch16. The timer 15 includes a frame 17 on which is rigidly mounted aswitch housing 18, preferably formed of a dielectric material, thatsupports the components of the switch 16.

The switch includes a pair of resilient contact arms 21, 22 anchored byterminals 23, 24 to the housing 18. The arm 21 is the movable member ofthe switch and it carries a pair of opposed contacts 25, 26. When thearm 21 is swung upwardly, the contact 25 is urged into engagement with acontact 27 carried by the arm 22.

Lowering the arm 21 brings the contact 26 into engagement with a contact28 which is carried by a fixed-term nal 29 mounted in the housing 18.Thus, lifting the arm 21 closes the contacts 25, 27 and opens thecontacts 26, 28, while lowering the arm 21 opens the contacts 25, 26 andcloses the contacts 26, 28.

To prevent the contacts 25, 27 from remaining in engagement when the arm21 is lowered, a lug 31, preferably formed as an integral portion of thehousing 18, engages the end of the arm 22 when the arm 21 is lowered(see FIG. 4) and positively holds the contacts 25, 27 apart.

For moving the arm 21, the arm is provided with an operator 32 in'theform of a pin or rod. The operator pin is secured to the arm 21 by beingfixed between a pair of depending flange portions 33 formed integrallywith the switch arm.

In accordance with the present invention, the operator 32 is biasedagainst a cyclically driven control cam having a drop-off portion, and atiming member is provided which blocks the operator from the camdrop-off portion. The timing member is driven through a cycle whoseduration is a multiple of the control cam cycle and is formed toperiodically free the operator for operation by the control cam.

In the illustrated embodiment, the operator 32 is urged against acontrol cam 35 by mounting the contact arm 21 so that its inherentresilience tends to swing the operator 32 against the control cam. Thecontrol cam 35 is provided with a drop-oil portion 36 having one side 37formed as a sloping cam surface.

In the preferred form of the invention, the control cam 35 is looselyjournaled on a shaft 41 and is driven in an oscillating cycle by a drivecam 42. The drive cam 42 is secured to an output shaft 43 of asynchronous timing motor 44 which drives the shaft 43 through speedreduction gears in a gear case 45. The drive cam 42 rotatescounterclockwise, as seen in the drawings, at a constant predeterminedrate when alternating cur-rent is supplied to the motor 44.

To enable the drive cam 42 to oscillate the control cam 35 through itscycle, the cam 35 is provided with a cam follower in the form of a pin46 and is biased by a tensioned spring 47 so as to urge the pin 46against the periphery of the drive cam 42. The drive cam is formed witha pair of drop-off steps 51, 52 connected by a spiral cam surface 53. Itmay thus be seen that as the drive cam 42 rotates in a counterclockwisedirection, the pin 52 is urged to the left by the cam surface 53 so asto swing the control cam 35 in a clockwise direction against the urgingof the spring 47. Upon further movement of the drive cam 42, the pin 46drops from the successive drop-off steps 51, 52 so that the control cam35 jumps in a counterclockwise direction under the urging of the spring47 to a first position as the pin 46 drops from the step 51, and then toa second position as the pin drops from the step 52. In other words, thecontrol cam 35 oscillates by slowly moving in a clockwise direction andthen jumping back in a counterclockwise direction through two steps toits original position.

The control cam 35 is phased so that its drop-off portion 36 is adjacentthe switch operator 32 when the cam has jumped to its first positionwith the pin 46 dropping from the step 51 (see FIG. 4).

In the illustrated embodiment, the member which blocks the operator 32from the drop-off portion 36 of the control cam takes the form of atiming cam 60 mounted coaxially with the control cam 35. The timing camis provided with a relieved peripheral or drop-off portion 61 and issecured to the shaft 41. The cam 60 is rotated by the motor 44 through apinion 62 carried by the output shaft 43 and a gear 63 mounted on theshaft 41 (see FIG. 2). Thus, the timing motor 44 cycles the timing cam60 in a clockwise direction while driving the control cam 35 through itsoscillating cycle.

The cycle of the timing cam 60 has a duration which is a multiple of thecycling interval of the control cam 35. In the illustrated embodiment,the control can 35 cycles, that is, makes a complete oscillation, sixtimes while the timing cam 60 cycles once, that is, makes one completerevolution.

To more readily understand the operation of the timer 15, a completeoperating cycle of the timer will be reviewed. Considering first FIG. 1,it will be appreciated that so long as the switch operator 32 rests onthe periphery of the timing cam 60, the oscillating control cam 35cannot operate the switch 16. The contacts 25, 27 thus remain closed andthe contacts 26, 28 open throughout the relatively long time intervalrequired to rotate the 3 timing cam 6t) so as to bring the relievedportion 61 adjacent the operator 32. In the preferred embodiment, thetiming member 66 cycles once every twelve hours.

When the timing cam 69 approaches the end of a cycle and the relievedportion 61 is brought adjacent the operator 32, as shown in FIG. 3, itwill be seen that the operator 32 rests solely on the control cam 35. Asthe control cam 35 cycles, the pin 46 drops from the step 51, see FIG.4, and the drop-d portions 36 and 61 are brought into alinement adjacentthe operator 32. Because of the resilience in the contact arm 21, thearm swings downwardly to open the contacts 25, 27 and close the contacts26, 2.8.

As the control cam 35 continues its cycle and jumps into its secondposition, that is, when the pin 46 drops from the step 52, the camsurface 37 urges the operator upwardly onto the periphery of the controlcam, and the contact arm 21 is restored to its original position withthe contacts 25, '7 closed and the contacts 26, 23 opened. Soonthereafter, the timing member 69, continuing its steady rotation, movessutiiciently far to carry the relieved portion 61 away from the operator32 so that subsequent cycles of the control cam 35 are ineffective tooperate the switch 16 until the timing cam 69 again completes its fullcycle.

It is important to note that when the switch 16 is operated, itsoperation is solely under the control of the cam 35 which moves quiterapidly, in spaced jumps, when operating the switch. Thus, the switchcontacts are moved quickly and positively into and out of contact andthere is no opportunity for fluttering or arcing.

The length of time during which the switch is operated is determined bythe spacing between the steps 51, 52 on the drive cam 42, that is, bythe length of a ledge 65 which connects the steps. In the illustratedembodiment, the ledge 65 is sufiiciently long to hold the switch 16operated for the period of three minutes. By selecting an appropriatelyproportioned drive cam 42, this time interval can be adjusted quiteaccurately.

It can now be understood that the timer is capable of reliably operatingthe switch 16 for an exactly determined relatively brief interval, threeminutes in the illustrated embodiment, once during a relatively muchlonger timing cycle, twelve hours in the illustrated example. However,since the switch 16 is snap-actuated, it can be seen that there is nodanger of arcing between the contacts despite the very long timing cycleinvolved.

Those skilled in the art will also appreciate that the timer 15 can beconstructed quite compactly and economically, since it utilizescomponents of standard types which can be easily formed by tools andtechniques common to the art.

I claim as my invention:

1. A mechanism actuating timer comprising, in combination, a timingmotor, a control cam, means for intermittently stepping said controlcam, said means being powered by said motor so that the control cam isstepped through repeating cycles, said cam having a drop-off portion, amechanism operator biased against said cam and being operated when saiddrop-off portion is alined therewith at one of said intermediate steps,a timing member for blocking said operator from said drop-0d portion,said timing member being driven by said motor through a cycle whoseduration is a multiple of said control cam cycle, and said member havinga relieved portion which periodically frees said operator for operationunder the control of said control cam.

2. A mechanism actuating timer comprising, in combination, a timingmotor, a timing cam coupled to said motor for rotation through arepeating cycle, a jump cam positioned adjacent said timing cam, amovable mechanism operator biased against the peripheries of said cams,each of said cams having drop-off portions permitting operation of saidoperator when said portions are each alined adjacent the operator, meanspowered by said motor for cycling said jump cam at a speed which is amultiple of said timing cam cycle, said means being ehfective to jumpsaid jump cam during its cycle with a snap action into and out of theposition at which the drop-off portion of the jump cam is adjacent saidoperator, said cams being phased so that once during each timing camcycle said drop-off portions coincide adjacent the operator and themechanism operator is operated.

3. A mechanism actuating timer comprising, in combination, a timingmotor, a timing cam coupled to said motor for movement of said camthrough repeating cycles, a control cam positioned adjacent said timingcam, a movable mechanism operator biased against said cams at a fixedlocation, each of said cams having drop-01f portions permittingoperation of said operator when the portions are alined at saidlocation, means powered by said timing motor for oscillating saidcontrol cam through repeating cycles, said means causing the control camto jump to first and second positions during its cycle, said cams beingphased so that every time the timing cam dropoil portion reaches saidlocation the control cam first jumps to its first position disposing itsdrop-off portion at said location, thus operating said mechanismoperator, and then the control cam jumps to its second position torestore the mechanism operator.

4. A mechanism actuatin timer comprising, in combination, a timingmotor, a circular timing cam coupled to said motor for rotation of saidcam through repeating cycles, a control cam positioned adjacent saidtiming cam and journaled coaxially therewith, a movable mechanismoperator biased against the peripheries of said cams at a fixedlocation, each of said cams having drop-off portions permittingoperation of said operator when the portions are alined at saidlocation, means for resiliently urging said control cam in onedirection, a drive cam coupled to said timing motor for oscillating saidcontrol cam through repeating cycles, the cycle of said timing cam beinga multiple of the cycle of said control cam, said drive cam havingspaced drop-off steps causing the resiliently urged control cam to jumpto first and second positions during its cycle, said cams being phasedso that every time the timing cam drop-off portion reaches said locationthe control cam first jumps to its first position disposing its drop-0dportion at said location, thus operating said mechanism operator, andthen the control cam jumps to its second position to restore themechanism operator.

References Cited in the file of this patent UNITED STATES PATENTS2,424,116 Puerner July 15, 1947 2,925,478 Yamasaki Feb. 16, 1960

